[clang][analyzer] fix crash when modelling 'getline'

vbvictor · vbvictor · commit 82f95795ee8e · 2025-06-23T23:17:26.000+03:00
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
@@ -1060,6 +1060,9 @@ impact the linker behaviour like the other `-static-*` flags.
 Crash and bug fixes
 ^^^^^^^^^^^^^^^^^^^
 
+- Fixed a crash in ``UnixAPIMisuseChecker`` and ``MallocChecker`` when analyzing
+  code with non-standard ``getline`` or ``getdelim`` function signatures.
+
 Improvements
 ^^^^^^^^^^^^
 
diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -1489,6 +1489,13 @@ void MallocChecker::preGetdelim(ProgramStateRef State, const CallEvent &Call,
   if (isFromStdNamespace(Call))
     return;
 
+  if (Call.getNumArgs() < 1)
+    return;
+
+  const Expr *Arg0 = Call.getArgExpr(0);
+  if (!Arg0->getType()->isPointerType())
+    return; // Skip checks if argument is not a pointer
+
   const auto LinePtr = getPointeeVal(Call.getArgSVal(0), State);
   if (!LinePtr)
     return;
@@ -1518,10 +1525,23 @@ void MallocChecker::checkGetdelim(ProgramStateRef State, const CallEvent &Call,
   if (!CE)
     return;
 
-  const auto LinePtr =
-      getPointeeVal(Call.getArgSVal(0), State)->getAs<DefinedSVal>();
-  const auto Size =
-      getPointeeVal(Call.getArgSVal(1), State)->getAs<DefinedSVal>();
+  if (Call.getNumArgs() < 2)
+    return;
+
+  const Expr *Arg0 = Call.getArgExpr(0);
+  const Expr *Arg1 = Call.getArgExpr(1);
+  if (!Arg0->getType()->isPointerType() || !Arg1->getType()->isPointerType())
+    return; // Skip checks if arguments are not pointers
+
+  auto LinePtrOpt = getPointeeVal(Call.getArgSVal(0), State);
+  if (!LinePtrOpt)
+    return;
+  const auto LinePtr = LinePtrOpt->getAs<DefinedSVal>();
+
+  auto SizeOpt = getPointeeVal(Call.getArgSVal(1), State);
+  if (!SizeOpt)
+    return;
+  const auto Size = SizeOpt->getAs<DefinedSVal>();
   if (!LinePtr || !Size || !LinePtr->getAsRegion())
     return;
 
diff --git a/clang/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/UnixAPIChecker.cpp
@@ -332,13 +332,21 @@ ProgramStateRef UnixAPIMisuseChecker::EnsureGetdelimBufferAndSizeCorrect(
 
   // We have a pointer to a pointer to the buffer, and a pointer to the size.
   // We want what they point at.
-  auto LinePtrSVal = getPointeeVal(LinePtrPtrSVal, State)->getAs<DefinedSVal>();
+  auto LinePtrValOpt = getPointeeVal(LinePtrPtrSVal, State);
+  if (!LinePtrValOpt)
+    return nullptr;
+    
+  auto LinePtrSVal = LinePtrValOpt->getAs<DefinedSVal>();
   auto NSVal = getPointeeVal(SizePtrSVal, State);
   if (!LinePtrSVal || !NSVal || NSVal->isUnknown())
     return nullptr;
 
   assert(LinePtrPtrExpr && SizePtrExpr);
 
+  // Add defensive check to ensure we can handle the assume operation
+  if (!LinePtrSVal->getAs<DefinedSVal>())
+    return nullptr;
+
   const auto [LinePtrNotNull, LinePtrNull] = State->assume(*LinePtrSVal);
   if (LinePtrNotNull && !LinePtrNull) {
     // If `*lineptr` is not null, but `*n` is undefined, there is UB.
@@ -350,9 +358,17 @@ ProgramStateRef UnixAPIMisuseChecker::EnsureGetdelimBufferAndSizeCorrect(
     // If it is defined, and known, its size must be less than or equal to
     // the buffer size.
     auto NDefSVal = NSVal->getAs<DefinedSVal>();
+    if (!NDefSVal)
+      return LinePtrNotNull; 
+    
     auto &SVB = C.getSValBuilder();
-    auto LineBufSize =
-        getDynamicExtent(LinePtrNotNull, LinePtrSVal->getAsRegion(), SVB);
+    
+    
+    const MemRegion *LinePtrRegion = LinePtrSVal->getAsRegion();
+    if (!LinePtrRegion)
+      return LinePtrNotNull;
+    
+    auto LineBufSize = getDynamicExtent(LinePtrNotNull, LinePtrRegion, SVB);
     auto LineBufSizeGtN = SVB.evalBinOp(LinePtrNotNull, BO_GE, LineBufSize,
                                         *NDefSVal, SVB.getConditionType())
                               .getAs<DefinedOrUnknownSVal>();
@@ -370,23 +386,29 @@ ProgramStateRef UnixAPIMisuseChecker::EnsureGetdelimBufferAndSizeCorrect(
 void UnixAPIMisuseChecker::CheckGetDelim(CheckerContext &C,
                                          const CallEvent &Call) const {
   ProgramStateRef State = C.getState();
+  if (Call.getNumArgs() < 2)
+    return;
 
+  const Expr *Arg0 = Call.getArgExpr(0);
+  const Expr *Arg1 = Call.getArgExpr(1);
+  
+  if (!Arg0->getType()->isPointerType() || !Arg1->getType()->isPointerType())
+    return; // Skip checks if arguments are not pointers
+  
   // The parameter `n` must not be NULL.
   SVal SizePtrSval = Call.getArgSVal(1);
-  State = EnsurePtrNotNull(SizePtrSval, Call.getArgExpr(1), C, State, "Size");
+  State = EnsurePtrNotNull(SizePtrSval, Arg1, C, State, "Size");
   if (!State)
     return;
 
   // The parameter `lineptr` must not be NULL.
   SVal LinePtrPtrSVal = Call.getArgSVal(0);
-  State =
-      EnsurePtrNotNull(LinePtrPtrSVal, Call.getArgExpr(0), C, State, "Line");
+  State = EnsurePtrNotNull(LinePtrPtrSVal, Arg0, C, State, "Line");
   if (!State)
     return;
 
   State = EnsureGetdelimBufferAndSizeCorrect(LinePtrPtrSVal, SizePtrSval,
-                                             Call.getArgExpr(0),
-                                             Call.getArgExpr(1), C, State);
+                                             Arg0, Arg1, C, State);
   if (!State)
     return;
 
diff --git a/clang/test/Analysis/getline-unixapi-invalid-signatures.c b/clang/test/Analysis/getline-unixapi-invalid-signatures.c
@@ -0,0 +1,127 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_CORRECT
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_1
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_2
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_3
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_4
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_5
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix -verify %s -DTEST_GETLINE_GH144884
+
+// emulator of "system-header-simulator.h" because of redefinition of 'getline' function
+typedef struct _FILE FILE;
+typedef __typeof(sizeof(int)) size_t;
+typedef long ssize_t;
+#define NULL 0
+
+int fclose(FILE *fp);
+FILE *tmpfile(void);
+
+#ifdef TEST_CORRECT
+ssize_t getline(char **lineptr, size_t *n, FILE *stream);
+ssize_t getdelim(char **lineptr, size_t *n, int delimiter, FILE *stream);
+
+void test_correct() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getline(&buffer, NULL, F1); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+
+void test_delim_correct() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getdelim(&buffer, NULL, ',', F1); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_1
+// expected-no-diagnostics
+ssize_t getline(int lineptr);
+
+void test() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  int buffer = 0;
+  getline(buffer);
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_2
+ssize_t getline(char **lineptr, size_t *n);
+
+void test() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getline(&buffer, NULL); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_3
+// expected-no-diagnostics
+ssize_t getline(char **lineptr, size_t n, FILE *stream);
+
+void test() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getline(&buffer, 0, F1);
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_4
+ssize_t getline(char **lineptr, size_t *n, int stream);
+ssize_t getdelim(char **lineptr, size_t *n, int delimiter, int stream);
+
+void test() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getline(&buffer, NULL, 1); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+
+void test_delim() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getdelim(&buffer, NULL, ',', 1); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_5
+ssize_t getdelim(char **lineptr, size_t *n, const char* delimiter, FILE *stream);
+
+void test_delim() {
+  FILE *F1 = tmpfile();
+  if (!F1)
+    return;
+  char *buffer = NULL;
+  getdelim(&buffer, NULL, ",", F1); // expected-warning {{Size pointer might be NULL}}
+  fclose(F1);
+}
+#endif
+
+#ifdef TEST_GETLINE_GH144884
+// expected-no-diagnostics
+struct AW_string {};
+void getline(int *, struct AW_string);
+void top() {
+  struct AW_string line;
+  int getline_file_info;
+  getline(&getline_file_info, line);
+}
+#endif
